:root{--bg:#0f172a;--card:#1e293b;--text:#e2e8f0;--muted:#94a3b8;--accent:#38bdf8}
@media (prefers-color-scheme:light){:root{--bg:#f8fafc;--card:#fff;--text:#0f172a;--muted:#475569;--accent:#0369a1}}
*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--text);font:16px/1.7 system-ui,-apple-system,Segoe UI,Roboto,sans-serif}
header,main,footer{max-width:820px;margin:0 auto;padding:20px 16px}
header{display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:8px}
nav a{margin-right:14px}a{color:var(--accent)}
h1{font-size:2rem;line-height:1.25}h2{margin-top:2rem}
.card{background:var(--card);border-radius:12px;padding:20px;margin:16px 0}
.muted{color:var(--muted);font-size:.9rem}footer{border-top:1px solid #64748b44;margin-top:40px}